Facebook has become the latest tech company to receive an ultimatum from the government: allow us access to encrypted data to help with a criminal investigation.

Reuters is reporting that at a sealed trial in California, the government has asked the court to hold the social networking company in contempt of court for refusing to allow law enforcement to access voice calls made in Facebook’s Messenger app. The case itself involves an investigation into the MS-13 gang, which the Trump administration (and other Republican candidates) use as a political football in the fight over immigration. Facebook says it is impossible to comply the request, because phone conversations on Messenger are encrypted end-to-end and there is no way for the company to access them.

The case is the latest in a series of battles between law enforcement and tech companies about access to the personal data and communications we give those companies and store on their devices–and what expectations we have when we do it. The last major front in this fight was when the FBI attempted to use the courts to force Apple to unlock the phone of the deceased San Berardino shooter, which was ultimately resolved not with a new legal precedent because the FBI found a different way to access the phone.

What will happen in this case, writes Reuters, could create major changes in who can access our data:

The potential impact of the judge’s coming ruling is unclear. If the government prevails in the Facebook Messenger case, it could make similar arguments to force companies to rewrite other popular encrypted services such as Signal and Facebook’s billion-user WhatsApp, which include both voice and text functions, some legal experts said.

Law enforcement agencies forcing technology providers to rewrite software to capture and hand over data that is no longer encrypted would have major implications for the companies which see themselves as defenders of individual privacy while under pressure from police and lawmakers.